A conventional beam splitter is configured to transmit signals quickly in an optical transmission manner, but during optical transmission, it is necessary to convert electrical signals into optical signals through a light emitting element and a monitor photo diode (MPD), thus monitoring light emitting state and adjusting luminescence of the light emitting element.
The conventional beam splitter contains a plurality of reflecting lens configured to split external beam to two sub beams of different paths from the light emitting element, and one of the two sub beams is collimated by collimating lens and projects on the monitor photo diode.
However, as splitting the external beam by using the plurality of reflecting lens, the light emitting element has to keep a distance from the monitor photo diode so that the plurality of reflecting lens refract the two sub beams, and the two sub beams project to the monitor photo diode, so the beam splitter cannot be miniaturized. Furthermore, it is troublesome to assemble the plurality of reflecting lens.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages.